Gold Leaching with Humic Substances

Abstract

The study results of gold leaching using the products of humic acids, as well as stage-by-stage fractionation of parent and gold-containing substances of these acids are presented. The gold content in the pregnant solution was up to 14–30 mg/l. Chemical analysis of the supernatant obtained by a stepwise change in pH of the solution and subsequent centrifugation determined that gold-bearing acids contain both organic and dissolved gold, which is stable to precipitation at pH 2. Fractionation of the original humic acids and subsequent leaching of gold by its individual fractions slows down the dissolution kinetics, and the fractions distinguished at different pH vary significantly in their activity. The most active is the fraction obtained by centrifugation at pH value of 4.6. The spectrum is presented, and the kinetics of gold dissolution by these acids modified by the cyanide complex is shown.